(1) Field of the Invention
The subject invention relates to a medicalsurgical tube such as that used in a catheter. The term "catheter" as used herein means any medical-surgical tube which includes a proximal end, a distal end and a longitudinal bore extending between the ends with the distal end having an opening. The catheter tubes are designed for insertion into some tissue, organ, cavity as, for example, a vascular or arterial branch, or the like, in a patient to serve as a channel for removing fluids from or introducing fluids into the tissue, organ, cavity, or the like, within the patient. Such catheters are frequently combined with syringes, valves, fluid traps or other units in creating assemblies required for the particular medical or clinical procedure being applied to the patient.
(2) Description of the Prior Art
Extensive use is being made of disposable catheters designed for single patient and single use. Such disposable catheters are most commonly produced by an extrusion of waterproof and inert plastic material which is nontoxic, nonabsorbitive and resistant to attack or deterioration by fluids of body tissue into which the catheter may be inserted in the course of a surgical or clinical procedure. In many surgical or clinical procedures, it is important to be able to determine the location or position of the catheter within the body of the patient into which it has been inserted. Furthermore, in some situations a tube inserted into the body of a patient may break off and it is imperative that a broken-off piece of tube be locatable. X-ray observation is a convenient method of making this position determination, but the usual plastic material from which catheters are made is not X-ray opaque, i.e., radiopaque. Accordingly, several catheter constructions have been devised in order to permit the body position of the catheter to be determined by X-ray observation. Such constructions include a radiopaque material combined or mixed with the plastic material of the catheter. However, the radiopaque material is frequently chemically reactive with body tissues and/or is rough or coarse and when exposed on the exterior of the catheter provides a relatively high coefficient of friction which causes irritation or impairs the insertion of the catheter into a tissue and when exposed to the interior of the tube provides a rough surface which frequently causes bruising of the blood which may, in turn, cause clotting. In some constructions the amount of radiopaque material is not sufficient for good detection of the placement of the catheter in all locations. If the amount of radiopaque material is increased for detection deep within the body, it may be unacceptable because of its roughness and/or because of it being too reactive. If the radiopaque material is sufficient for adequate radiopacity, the surface roughness and chemical reactivity is a problem and if reduced there may not be sufficient radiopacity.